Plant growth-promoting potentials of sweet sorghum bagasse compost S. Gopalakrishnan Principal Scientist (Microbiology) ICRISAT
Introduction Sweet sorghum is a major feed stock for both sugar based (1G) and ligno-cellulosic (2G) ethanol production. Sugar extraction from stalks provides bagasse as a byproduct, representing about 30% of the plant fresh weight. Bagasse is used for livestock feed, co-generation of power and organic soil amendment. Direct amendment of bagasse in soil also leads to phytotoxicity and soil nitrogen immobilization. Composting of bagasse is recommended, as they are safe and beneficial to plant growth.
Composting of sweet sorghum bagasse Bagasse contains low levels of nutrients (both macro and micro) although it is rich in organic C, giving it a high CN ratio. Hence, N rich organic material added to bagasse in order to obtain the optimum initial CN ratio of 25 required for composting. Objectives: 1. Standardize amendments required for efficient composting of bagasse 2. Standardize microbes for efficient composting of bagasse. 3. Evaluate the PGP and biocontrol traits of microbes that can enhance the final product of bagasse compost that include N 2 - fixers, p-solubilizers and producers of siderophore, indole acetic acid, ß-1,3-glucanase, chitinase, lipase and hydrocyanic acid. 4. Evaluate the value added bagasse compost for their PGP in sorghum
Amendments and microbes used in this study Bagasse and amendments such as rice straw; FYM; fallen leaves @ 2:1 and 3:1; N and P requirement, Locally available earthworms were also used. Microbes: 1. Myceliophthora thermophila (ATCC-48104) 2. Aspergillus awamori Fungi (3) 3. Chaetomium virescens (ATCC-32319) 4. Bacillus subtilis (ATCC-6633) 5. Bacillus aquimaris (MP-4) 6. Bacillus licheniformis (MP-6) Bacteria (6) 7. Bacillus infantis (MP-7) 8. Bacillus flexus (MP-8) 9. Bacillus sp. (BCB-19) 10. Streptomyces sp. (MAI-1) Actinomycetes (1)
Protocol used for composting bagasse A total of 10 kg (Pilot study) or 200 kg (Large scale) of organic wastes (SB-rice straw/fym) in 3:1 ratio. Soaked in water for 5 min. Disperse rock phosphate (5%), nitrogen (0.38%) and cow dung slurry (10 kg in 15 L water) in organic waste. Disperse microbial cultures (one pocket of 70g; contains 10-8 cells g -1 ) layer by layer, mix and transfer into the pits/ground Cover the pits/heap with rice straw bundle in nets and un-disturb for 15-20 days. At the end of 20 days, mix it well and add water if required. Cover the pits/heap again and undisturbed for another 10 days. At the end of 30 days, repeat the above step and add earthworms (about 500 numbers) and terminate at 60 days.
D O N O T C O PY Setting up of pilot scale study (10 kg)
C O PY Large scale Study (200kg) Incorporating amendments Arrangement of heap D O N O T Soaking of bagasse Final shape of heap Mixing after 20 days Release earthworms
SB+ rice straw A. awamori C O PY Pilot scale study: Composting of sorghum bagasse with rice straw and microbes @ 30 DAS M. thermophila B. subtilis D O N O T FYM and microbes @ 30 DAS SB+ FYM A. awamori M. thermophila B. subtilis
A. awamori M. thermophila B. subtilis O T SB+ Rice straw C O PY Large scale up- Composting of bagasse with rice straw and microbes @ 30 DAS D O N FYM and microbes @ 30 DAS SB+ FYM A. awamori M. thermophila B. subtilis
Pilot scale study: Composting of bagasse using rice straw and microbes @ 60 DAS S. NO. Treatment Initial weight kg Total Dry compost (kg) % Degradation Visual Rating 1 SB: Rice straw (3:1) 10.5 4.8 54 2 2 SB: Rice straw (3:1) + A.awamori 10.7 3.8 64 4 3 SB: Rice straw (3:1)+ M. thermophila 10.7 3.7 65 4 4 SB: Rice straw (3:1) + B. subtilis 10.7 3.6 65 4 5 SB: Rice straw (3:1) + C.virescens 10.7 4.1 61 4 6 SB: Rice straw (3:1) + MAI-1 10.7 4.5 57 2 7 SB: Rice straw (3:1) + BCB-19 10.7 4.13 61 4 8 SB: Rice straw (3:1) + MP-4 10.7 4.34 59 2 9 SB: Rice straw (3:1) + MP-6 10.7 4.4 58 2 10 SB: Rice straw (3:1) + MP-7 10.7 4.3 59 3 11 SB: Rice straw (3:1) + MP-8 10.7 4.1 61 4 SB= Sorghum bagasse; Visual rating: 1= Low, 2= Average, 3= Good, 4= Very Good
Pilot scale study: Micronutrients analysis of bagasse compost: rice straw and microbes @ 60 DAS Treatment Fe ppm Cu ppm Mn ppm Zn ppm Ca ppm Mg ppm Ash % Total P% Total K% SB: RS 2310 7.8 154 60.1 19416 3843 24.6 1.09 1.89 SB: RS + A. awamori 2192 8.1 163 51.5 19376 3904 24.9 1.16 1.91 SB: RS + M. thermophila 2740 7.9 188 48.5 21574 3983 25.4 1.28 1.98 SB: RS + B. subtilis 3078 9.4 203 45.5 21863 4082 23.9 0.99 1.95 SB: RS + C. virescens 3374 8.4 125 46.9 16236 4283 26.8 0.73 1.28 SB: RS + MAI-1 3130 8.5 177 48.0 19084 4920 25.2 1.03 1.31 SB: RS + BCB-19 4007 9.0 161 48.9 19188 4544 33.4 0.89 1.39 SB: RS + MP-4 4584 10.1 158 52.5 19123 5150 32.2 0.94 1.34 SB: RS + MP-6 4213 9.9 177 51.4 18474 4616 32.0 0.85 1.31 SB: RS + MP-7 3598 9.3 156 55.9 19958 5413 29.7 1.14 1.33 SB: RS + MP-8 3630 9.0 138 47.6 16247 4576 29.7 0.82 1.39 Mean 3351 8.9 164 50.6 19140 4483 28.0 0.99 1.55 SE± 152.0*** 0.32** 10.2** 1.14*** 695.2** 78.7*** 0.96*** 0.055*** 0.030*** LSD (5%) 478.9 1.01 32.1 3.58 2190.6 248.1 3.03 0.174 0.095 CV% 6 5 9 3 5 3 5 8 3
Pilot scale study: Composting of bagasse using FYM and microbes @ 60 DAS S.NO. Treatment Initial weight kg Total Dry compost (kg) % Degradation Visual Rating 1 SB: FYM (3:1) 10.5 5.4 48 1 2 SB: FYM (3:1) + A. awamori 10.7 4.2 60 4 3 SB: FYM (3:1)+ M. thermophila 10.7 4.9 53 2 4 SB: FYM (3:1) + B. subtilis 10.7 4.9 53 2 5 SB: FYM (3:1) + C. virescens 10.7 5.6 44 1 6 SB: FYM (3:1) + MAI-1 10.7 5.8 45 1 7 SB: FYM (3:1) + BCB-19 10.7 5.9 44 1 8 SB: FYM (3:1) + MP-4 10.7 5.6 46 1 9 SB: FYM (3:1) + MP-6 10.7 5.5 48 1 10 SB: FYM (3:1) + MP-7 10.7 5.7 46 1 11 SB: FYM (3:1) + MP-8 10.7 5.8 45 1 SB= Sorghum bagasse, FYM= Farm yard manure; Visual rating: 1= Low, 2=Average, 3= Good, 4= Very Good
Pilot scale study: Micronutrients analysis of bagasse compost: FYM and microbes @ 60 DAS Treatment Fe ppm Cu ppm Mn ppm Zn ppm Ca ppm Mg ppm Ash % Total P% Total K% SB: FYM 4369 10.3 154 50.6 20424 3438 44.7 1.04 1.07 SB: FYM + A. awamori 5079 11.5 186 63.5 23279 3794 48.8 1.05 1.24 SB: FYM + M. thermophila 4637 10.7 164 51.3 21334 3496 45.5 0.94 1.11 SB: FYM + B. subtilis 4516 10.2 164 51.8 21131 3734 47.0 0.89 1.11 SB: FYM + C. virescens 4461 9.3 140 52.3 17427 3696 48.0 0.78 0.92 SB: FYM + MAI-1 4169 9.1 117 48.9 16406 3782 36.4 0.73 0.94 SB: FYM + BCB-19 5347 11.0 139 54.6 18229 3836 52.0 0.75 0.96 SB: FYM + MP-4 4554 9.1 142 51.2 21496 4165 52.2 0.71 0.92 SB: FYM + MP-6 4004 9.6 127 52.6 16440 3800 47.4 0.73 1.03 SB: FYM + MP-7 4276 10.0 116 54.2 17508 4026 46.7 0.70 1.11 SB: FYM + MP-8 3756 9.4 114 52.7 17611 4514 39.4 0.88 1.06 Mean 4470 10.0 142 53.1 19208 3844 46.2 0.83 1.04 SE± 138.3*** 0.47* 9.6** 1.24*** 800.7*** 128.4** 2.09** 0.032*** 0.044** LSD (5%) 435.9 1.47 30.2 3.91 2523.1 404.5 6.60 0.101 0.138 SB: FYM 4 7 10 3 6 5 6 6 6
Large scale up: Composting of bagasse using rice straw and FYM with three promising microbes @ 60 DAS S. No Treatment Initial weight kg At 60 DAS (Final) Total wet wt kg Moisture % Total Dry compost (kg) % Degradation 1 SB +Rice-straw (RS; Control) 221.5 291.4 70 83 52 3 2 SB + RS+ A. awamori 222.9 316.4 74 77 66 4 3 SB + RS + B. subtilis 222.9 306.7 69 90 60 2 4 SB+ RS + M. thermophila 222.9 320.8 75 80 64 4 5 SB +FYM (Control) 221.5 291.2 63 101 50 2 6 SB + FYM+ A. awamori 222.9 252.9 62 86 61 4 7 SB + FYM+ B. subtilis 222.9 283.3 65 90 60 4 8 SB+FYM+ M. thermophila 222.9 267.0 66 83 63 4 Visual rating: 1= Low, 2= Average, 3= Good, 4= Very good Visual rating
Large scale up: Micronutrient analysis of bagasse compost: rice straw and FYM of 3 promising microbes @ 60 DAS Treatment Fe ppm Zn ppm Cu ppm Mn ppm Ca ppm Mg ppm Total N% SB + Rice-straw (RS) 7568 60.5 11.1 777 40132 4986 1.71 1.07 1.45 34.1 SB + RS+ A. awamori 5507 58.2 11.0 880 50818 4856 1.96 1.29 1.57 34.8 SB + RS + B. subtilis 8096 66.2 14.0 830 43868 5338 1.83 1.12 1.59 37.2 SB + RS + M. thermophila 5362 62.0 13.4 710 39854 4734 1.86 1.11 1.46 34.8 SB+ FYM 5088 76.4 21.0 720 41798 5010 1.61 0.98 1.07 43.6 SB + FYM + A. awamori 5254 81.3 20.5 734 32302 5519 1.61 1.10 1.19 56.0 SB + FYM + B. subtilis 12177 77.6 20.2 1116 36781 5400 1.54 0.94 1.27 52.0 SB + FYM + M. thermophila 7034 106.4 21.9 712 35025 5521 1.97 1.21 1.13 48.2 Mean 7011 73.6 16.6 810 40072 5171 1.76 1.10 1.34 42.6 SE± 299.9 *** 1.18 *** 0.39 *** 1800.1* 46.7 ** * 37.5 *** 0.033 *** 0.032 ** 0.639** 0.022 *** * LSD (5%) 1003.0 3.95 1.31 156.0 6019.6 125.3 0.109 0.108 0.076 2.135 CV% 6 2 3 8 6 1 3 4 2 2 Total P% **= Statistically significant at 0.01, ***= Statistically significant at 0.001 Total K% Ash (%)
Conclusions of pilot and large scale study Standardized the amendments required: 3:1 (bagasse: RS/FYM), RP, urea and earthworms. Standardized the best three microbes suitable for composting (A. awamori, M. thermophila and B. subtilis), based on % degradation and enrichment of micronutrients. The 3 selected microbes significantly increases Fe, Cu, Zn, Mn, Ca, Mg, B, S, Total N P K and ash content over the remaining treatments and control at 60 DAS.
PGP and biocontrol traits of the microbes used in composting of bagasse
IAA Isolate IAA (µg/ml) B. subtilis 8.7 BCB-19 13.9 MP-4 13.2 MP-6 12.3 MP-7 9.3 MP-8 77.5 MAI-1 57.3 A. awamori 8.1 M. thermophila 16.5 C. virescens 12.0 C Isolate Siderophore % Units B. subtilis 0 BCB-19 0 MP-4 0 MP-6 0 MP-7 0 MP-8 0 MAI-1 0 A. awamori 36 M. thermophila 0 C. virescens 0 C P P P P C = Control P = Positive Isolate HCN Rating B. subtilis 3 BCB-19 2 MP-4 1 MP-6 2 MP-7 3 MP-8 1 MAI-1 2 A. awamori 0 M. thermophila 0 C. virescens 0 Rank for HCN 1= light reddish brown, 2= medium reddish brown, 3= dark reddish brown
Cellulase activity Isolate Cellulase B. subtilis 4 BCB-19 4 MP-4 3 MP-6 3 MP-7 3 MP-8 3 MAI-1 4 A. awamori 3 M. thermophila 4 C. virescens 3 Isolate Lipase activity Lipase B. subtilis 2 BCB-19 3 MP-4 3 MP-6 3 MP-7 2 MP-8 3 MAI-1 5 A. awamori 5 M. thermophila 0 C. virescens 0 Chitinase activity Isolate Chitinase B. subtilis 1 BCB-19 0 MP-4 0 MP-6 0 MP-7 0 MP-8 0 MAI-1 3 A. awamori 0 M. thermophila 0 C. virescens 0 Rank for Cellulase, Lipase, Chitinase (in mm) 1= 0-10, 2= 11-20, 3= 21-30, 4= 31-40, 5= 41-50
Phosphate solubilization Isolate P- solubilization B. subtilis 1 BCB-19 0 MP-4 0 MP-6 0 MP-7 0 MP-8 2 MAI-1 0 A. awamori 4 M. thermophila 0 C. virescens 0 Isolate Protease activity Protease B. subtilis 3 BCB-19 0 MP-4 2 MP-6 2 MP-7 3 MP-8 3 MAI-1 4 A. awamori 0 M. thermophila 2 C. virescens 0 Rank for P solubilization, Protease (in mm) 1= 0-10, 2= 11-20, 3= 21-30, 4= 31-40, 5= 41-50
Antagonistic activity against Charcoal rot of sorghum Isolate R. bataticola-6 R. bataticola-24 R. bataticola-115 M. phaseolina B. subtilis 5 5 1 3 BCB-19 6 8 5 6 MP-4 0 0 0 0 MP-6 0 4 0 0 MP-7 0 0 0 0 MP-8 0 0 0 0 MAI-1 13 12 6 14 A. awamori 2 0 0 0 M. thermophila 0 0 0 0 C. virescens 0 0 0 0 a B. subtilis against a). Rhizoctonia bataticola-24; b) Macrophomina phaseolina b
Conclusions So for Identified 3 promising microbes (A. awamori, M. thermophila and B. subtilis) suitable for composting of SB. The 3 selected microbes significantly increases macro- and micronutrient contents. All 3 were found to produce many PGP & biocontrol traits including IAA, HCN, siderophore, cellulase, protease, chitinase and lipase. These were also found to solubilize P and inhibit pathogens of charcoal rot of sorghum.
Evaluation of value added bagasse-compost for their PGP activity on sweet sorghum
Greenhouse study Pot mixture: black soil, sand and bagasse compost @ 3:2:1 and 3:2:2. Sweet sorghum variety used: ICSV-93046 (matures at 110 120 days). Seeds were surface sterilized and sown in 8 inch pots (3 seeds/pot but thinned to one after one week). Plants were irrigated once every three days with sterilized distilled water. Observations: At 35 days after sowing (DAS): Plant height, leaf area, leaf weight, root length, root volume, shoot weight and root weight. At 70 DAS: Plant height, shoot and root weight. At harvesting: Plant height, panicle length, shoot weight, panicle weight, seed weight and number of seeds.
Treatments NO Treatment Samples 1 T1 SB+RS (Control) (3:2:1) 2 T2 SB+RS+ A. awamori 3 T3 SB+RS+ Myceliophtora thermophila 4 T4 SB+RS+ B. subtilis 5 T5 SB+FYM (Control) (3:2:1) 6 T6 SB+FYM+ A. awamori 7 T7 SB+FYM+ Myceliophtora thermophila 8 T8 SB+FYM+ B. subtilis 9 T9 SB+RS (Control) (3:2:2) 10 T10 SB+RS+ A. awamori 11 T11 SB+RS+ Myceliophtora thermophila 12 T12 SB+RS+ B. subtilis 13 T13 SB+FYM (Control) (3:2:2) 14 T14 SB+FYM+ A. awamori 15 T15 SB+FYM+ Myceliophtora thermophila 16 T16 SB+FYM+ B. subtilis!6 treatments Three microbes used T1-T8 = 3:2:1 T9-16 = 3:2:2 3:2:1= Black soil 3: Sand 2: Bagasse compost 1 3:2:2= Black soil 3: Sand 2: Bagasse compost 2 SB = Sorghum bagasse, RS = Rice Straw FYM= Farm Yard Manure
Effect of bagasse compost (3:2:1) prepared with microbes amended with rice straw and FYM on sweet sorghum at 35 DAS SB+ RS (Control) SB+ RS with A. awamori SB+ RS with M. thermophila SB+ RS with B. subtilis SB+ FYM (Control) SB+ FYM with A. awamori SB+FYM with M. thermophila SB+ FYM with B. subtilis
Effect of bagasse compost (3:2:2) prepared with microbes amended with rice straw and FYM on sweet sorghum at 35 DAS SB+ RS (Control) SB+ RS with A. awamori SB+ RS with M. thermophila SB+ RS with B. subtilis SB+ RS (Control) SB+ FYM with A. awamori SB+ FYM with M. thermophila SB+ FYM with B. subtilis
Effect of bagasse compost on plant height @ 35 DAS Plant height (cm) 100 80 60 40 20 0 37-44% 3:2:1 3:2:2 1-6% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Soil ratio 3:2:1 (T1-T8) Treatments 5-12% 8-10% Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on leaf dry weight @ 35 DAS Leaf dry weight (g) 2.5 2.0 1.5 1.0 0.5 0.0 3:2:1 3:2:2 63-81% 0.1-6% 6-9% 0.2-21% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on shoot dry weight @ 35 DAS Shoot dry weight (g) 2.5 2.0 1.5 1.0 0.5 0.0 3:2:1 3:2:2 38-66% 8-36% 49-81% 10-37% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on root dry weight @ 35 DAS Roor dry weight (g) 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 3:2:1 3:2:2 87-89% 23% 42-60% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Soil ratio 3:2:1 (T1-T8) Treatments Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on leaf area @ 35 DAS Leaf area 900 800 700 600 500 400 300 200 100 0 75-83% Leaf area(cm 2 ) 3:2:1 3:2:2 2-3% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) 10-27% 0-13% Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on root length @ 35 DAS Root length (cm/m 3 ) 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 Root length (cm/m 3 ) 3:2:1 3:2:2 37-48% 3% 21-26% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on shoot dry weight @ 70 DAS Shoor weight (g) 100 90 80 70 60 50 40 30 20 10 0 3:2:1 3:2:2 40-58% 5-32% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on root dry weight @ 70 DAS Root dry weight (g) 9 8 7 6 5 4 3 2 1 0 3:2:1 3:2:2 24-38% 7-36% 21-35% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Soil ratio 3:2:1 (T1-T8) Treatments Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on shoot dry weight @ Harvest Shoot weight (g) 70 60 50 40 30 20 10 0 3:2:1 3:2:2 30-46% 11-37% 31-41% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on panicle dry weight @ Harvest Panicke dry weight (g) 20 18 16 14 12 10 8 6 4 2 0 3:2:1 3:2:2 40-51% 1-22% 8-19% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Soil ratio 3:2:1 (T1-T8) Treatments Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on number of grains @ Harvest No of Grains /plant 600 500 400 300 200 100 0 3:2:1 3:2:2 20-62% 4-24% 11-15% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatment Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Effect of bagasse compost on grain weight @ Harvest Seed weight (g) 18 15 12 9 6 3 0 3:2:1 3:2:2 37-65% 2-24% 13-20% T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 Treatments Soil ratio 3:2:1 (T1-T8) Soil ratio 3:2:2 (T9-T16) T1 SB+RS (Control) T5 SB+FYM (Control) T9 SB+RS (Control) T13 SB+FYM (Control) T2 SB+RS+ A.awamoori T6 SB+FYM+ A.awamoori T10 SB+RS+ A.awamoori T14 SB+FYM+ A.awamoori T3 SB+RS+ Myceliophtora T7 SB+FYM+ Myceliophtora T11 SB+RS+ Myceliophtora T15 SB+FYM+ Myceliophtora T4 SB+RS+ B.subitilIs T8 SB+FYM+ B.subitilIs T12 SB+RS+ B.subitilus T16 SB+FYM+ B.subitilus
Conclusions Bagasse compost prepared with rice straw (as amendment) @ 3:2:1 along with microbes significantly and consistently enhanced all the PGP traits including plant height (37-44%), leaf dry weight (63-81%), shoot dry weight (38-66%), root dry weight (87-89%), leaf area (75-83%) and root length (37-48%) at 35 DAS; shoot dry weight (40-58%) and root dry weight (24-38%) at 70 DAS and shoot dry weight (30-46%), panicle dry weight (40-51%), number of grains/plant (20-62%) and grain weight/plant (37-65%) at harvest. Among the three microbes tested, Aspergillus awamori and Myceliophtora thermophila significantly and consistently enhanced all the PGP traits compared to Bacillus subtilis.
Overall conclusions Identified 3 promising microbes (A. awamori, M. thermophila and B. subtilis) suitable for composting of SB. The 3 selected microbes significantly enhances macro- and micronutrient contents. All 3 were found to produce PGP & biocontrol traits including IAA, HCN, siderophore, cellulase and chitinase. Also solubilize P and inhibit M. phaseolina. All 3 were also found significantly enhance traits including shoot weight, root weight, panicle weight, grain number and weight. Among the 3, A. awamori and M. thermophila significantly and consistently enhanced all the PGP traits compared to B. subtilis.
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